UE Idle Mode Cell Reselection via System Information Failure

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Solution Overview

Problem

In wireless communication networks, user equipment (UE) in idle mode experiences frequent cell reselection failures due to poor signal quality, leading to time-consuming and power-consuming initial cell selection procedures, resulting in missed calls and reduced in-service time.

Innovation Solution

The UE performs fast cell reselection based on system information reception failures instead of cell signal measurements, maintaining network sessions and selecting the highest priority neighboring cell with better signal measurements, and restricting the number of attempts using timers and counters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the UE performs conventional cell reselection based on signal quality measurements, then the UE can maintain connection quality, but the frequent reselection failures due to poor signal quality lead to time-consuming initial cell selection procedures and reduced in-service time

Engineering Contradiction:
Improvecell reselection success rateVSAvoidin-service time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent changes the basis for cell reselection from signal quality measurements to system information reception status. When system information reception fails, the UE triggers cell reselection immediately without waiting for signal quality degradation, fundamentally altering the reselection trigger parameter from physical layer measurements to higher-layer protocol status

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements preliminary cell reselection action by triggering reselection upon system information reception failure before the UE would otherwise declare out-of-service. This preliminary action prevents complete service interruption and avoids the time-consuming initial cell selection procedure that would follow a full out-of-service declaration

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the UE declares out-of-service error upon cell reselection failure, then the UE can reset and perform initial cell selection, but this process is time-consuming and power-consuming, resulting in missed calls

Engineering Contradiction:
Improvenetwork session continuityVSAvoidcall setup time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies beforehand cushioning by maintaining the network session in a suspended state rather than declaring out-of-service immediately upon reselection failure. This cushioning approach preserves the existing network context and session state, providing a buffer that allows rapid resumption without complete re-initialization

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent extracts the cell reselection failure condition from the out-of-service declaration trigger. By separating these two events, the system can handle reselection failures locally without propagating the out-of-service state, thereby avoiding the time-consuming initial cell selection procedure and associated missed calls

Inventive Principle:
Principle #2Taking out (Extraction)

3Speed

If the UE performs frequent cell reselection attempts without restriction, then the UE can find a suitable cell faster, but unrestricted attempts consume excessive power and increase device complexity

Engineering Contradiction:
Improvecell reselection speedVSAvoidpower consumption
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic action through configured timers that control the frequency and timing of cell reselection attempts. These timers create structured, periodic retry behavior rather than continuous or unrestricted attempts, allowing the system to balance speed of reselection with power consumption by spacing out measurement and evaluation cycles

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent applies dynamics by making the cell reselection process adaptive through timer-based control mechanisms. The system dynamically adjusts the aggressiveness of reselection attempts based on network conditions and timer expiration, allowing faster reselection when conditions permit while conserving power when conditions are unfavorable

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3949525B1Increase in-service time and robustness for sustained mobility in idle mode
Publication Date: 2024.01.10 QUALCOMM INC
  • EP3949525B1 patent drawingFigure 1
  • EP3949525B1 patent drawingFigure 2~3
  • EP3949525B1 patent drawingFigure 4

AI summary

Wireless communications systems and methods related to user equipment (UE) idle mode mobility in a wireless communication network are provided. A wireless communication device establishes a network session with a wireless communication network. The wireless communication device reselects a first cell for camping, wherein the first cell is associated with the wireless communication network. The wireless communication device monitors for first system information from the first cell. The wireless communication device reselects a second cell for camping in response to a failure to receive the first system information. The second cell is associated with the wireless communication network and different from the first cell. The wireless communication device maintains the network session during the reselecting the first cell for camping and the reselecting the second cell for camping.